This invention relates to a high frequency incising device for incision of the Vater's papilla within the duodenum and, more particularly, to an incising device with a stabilized electrically conductive wire that does not deviate from a desired direction of incision.
Devices for incising the Vater's papilla are usually introduced through the forceps channel of an endoscope into the body cavity by direct observation through the endoscope in accordance with a method of surgical papillary incision characterized as endoscopic papillectomy.
This surgical method is used for choledocholithiasis or benign papillary constriction, in which the sphincter muscle of duodenum Vater's papilla into which the common bile duct opens is endoscopically incised to enlarge the opening thereof so that stones produced within the common bile duct may be spontaneously discharged or seized and picked out by a litholabe introduced through the incision into the common bile duct.
The incising device conventionally used for this papillectomy typically comprises a flexible tube introduced into the forceps channel of the endoscope and provided adjacent its tip with a pair of longitudinally spaced through holes. One end of an electrically conductive wire is anchored to the tip of the tube by a metallic pipe. A portion of the wire is exposed outside the tube between the pair of through holes, and a manipulator unit is provided at a rear end of the tube, wherein an opposite end of the wire is connected such that operation of the manipulator unit controls protrusion or retraction of the wire through the rear through hole.
One known type of incising device is generally classified as the push type wherein the wire is caused to bulge out laterally from the tube between the pair of through holes in a semicircular form as the wire is pushed forward within the tube. Another known type of prior art incising device is generally classified as the pull type in which the tube is forcibly curved between the pair of through holes to cause the exposed wire to define a chord of semicircular form.
In both categories of the known incising devices a sufficient quantity of contrast medium is injected through an inlet at the rear end of the tube into the common bile duct. The contrast medium is used to confirm whether the tip of the incising device has been correctly inserted into the common bile duct on the basis of an image contrast provided by an X-ray taken before the actual incision is carried out using high frequency current. A highly skillful manipulation of the known devices is required to achieve an incision of the proper depth, since an incision that is too deep may cause profuse bleeding which can lead to other problems, and an incision that is too small will prevent adequate removal of stones.
It is thus desirable to provide an incising device that can be easily controlled to provide an accurate incision of Vater's papilla.